Any musicologist will tell you that string instruments go back millennia. Although that particular string musical instruments have changed, many of the principles are exactly the same. String instruments were essentially a development of the bow. A bow and arrow was one of the first big technological advances because it allowed hunters to successfully kill an animal that they could not catch. Surely, it wasn't long before they noticed that a pleasing sound could be made by plucking the bow. The rest is history.
Fascinatingly, although the principles behind string instruments are really ancient, the instruments themselves are still at the forefront of music even to this day. The piano, the guitar, the violin, the cello most of the most important instruments out there are played by picking, hammering, or bowing strings. Within this family, however, there is quite a bit of variety. A lot of care has to be taken before picking out the string instrument that is right for you.
A lot of people pay attention to which string instruments are easier or harder to learn. It is a well-known fact, for example, that guitar is easier to play than mandolin which, in turn, is easier to play than violin. I tend to stay away from this approach anyway, however, because it disguises one basic fact: pretty much anyone can learn to play any stringed instrument. The key is to listen to them and decide which one you like the most. The guitar is a great instrument to learn if you want to accompany your singing or to play rock 'n roll. The mandolin has a more classical feel to it, and the violin is one of the most stupendous solo instruments that has ever been created. All of them have strengths and weaknesses, so choose carefully.
Sometimes it pays to have a friend who plays string instruments. There are a lot of people out there who play several different instruments, and they can really break it down for you, helping you to pick out the best one to start with. A lot of people believe that if you want to play something in the guitar family, you might as well start with guitar. You can always pick up banjo or mandolin later, and the guitar is the easiest one to start out with. Then again, if you're really intent on being a musician, you might want to go all the way and learn keyboard. It is the best instrument for arranging and is great to learn if you want to understand music inside and out.